System for the transmission and reception of radiant energy



Aug. 7, 1923.v 1,463,994

J. H. HAMMOND, JR

SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY Original Filed Feb. 15, 1918 9 Sheets$heet 'l HIS ATTORNEY Au 7, 1923. R 1,463,994

J. H. HAMMOND. JR

SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY Original Filed Feb. 15, 1918 9 Sheets-Sheet 2' WITNESS: INVENTOR Hi8 ATTORNEY J. H. HAMMOND. JR

S'x'BTI'IM FOR THE TRANSMISSION AND RECEPTION OF RADTAN'F ENERGY Original Filed Feb. 15, 1918 9 Sheets$heotjn WIT/V555: INVENTOR H/S Afro/Mm Aug. 7, 1923. 1,463.994

J. H. HAMMOND, JR

SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENER GY Original Filed Feb. 15, 1918 9 Sheets-Sheet W/T/VESS; INVENTOR Aug. 7, 1923. 1,463,994 J. H. HAMMOND. JR

SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY Original Filed Feb. 15, 1918 9 Sheets-Sheet 5 W/TNESS M/VEIVTUR '1 [I l! u I HIS Arrohlvfr Aug. 7, 1923. 1,463,994

- J. H. HAMMOND JR SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY Original Filed Feb. 15, 1918 9 Sheets-Sheet f 581 gaz c5 551 l 1 AM I w 615 E 618 v 1111 620 551 l .15 621 614 Armn 5.91 "nun (0) 586 592 HHH ESS INVENTOR 1 r/ l a 5/ Q/ QM Aug. 7, 1923. 1,463.994

J. H. HAMMOND, JR

SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY Original Filed Feb. 15, 1915; 9 Sheets-Sheet 7 INVENTOR MW 'HIS ATTORNEY SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY Original Filed Feb. 15, 1918 9 Sheets-Sheet IlllllgllllllllIk- -E: 685

M L IIIlIIIIIMIH. Q Y 684' WITNESS INVENTOR Hi6 ATTORNEY J. H. HAMMOND. JR

SYSTEM FOR'THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY ori ina Filed Feb. 15, 1918 9Sheets-Sheet 9 WITNESS: l/V VE/V T01? Hi8 Arm/Mr Patented An 7, 1923.

UNW' ST JOHN HAYS HAMMOND, JR., OF GLOUCESTER, MASSACHUSETTS.

SYSTEM FOR THE TRANSMISSION AND RECEPTION OF RADIANT ENERGY.

Application filed February 15, 1918, Serial No. 217,425. Renewed October 31, 1922. Serial No. 598,208.

To all #710121 if may (mu-cm Be it known that I. JOHN Hays l-lAMMom). J12, a citizen of the United States, and resident of Gloucester. in the county of Essex, State of filassachusctts. have invented certain new and useful Improvements in Systems for the Transmission and Recep tion of Radiant Energy. of which the following is a specification.

Some of the objects of this invention are: to provide a group transmission system of radiant energy; to provide an improved re ceiving system for radiant energy: to provide an improved method for the transmis sion of radiant energy; to provide an improved system for the transmission of radiant energy whereby secrecy of operation may be maintained and interference may be avoided; and to provide a selective system for the transmission of radiant energy wherein a plurality of wave trains or series of waves are simultaneously emitted in such a manner that there will he a prtuletcrmined difference in phase relationship be tween different series or trains ot'wavcs and wherein the plurality of scrics or trains ol waves are selectively rcccivcd l v a receiving system in such a manner that a receiving device. forming part of the receiving system, is caused to operate onl as a result of the predctern'iined ditlcrencc in phase of the received waves.

In the accompanying. drawings. all of which are diagraimnatic views of systems constructed in accordance with this invention. Figs. land 2 are views respectively of two different forms ot transmission systems; Figs. 3 and 4 are views rcspcctivcl of two different forms of rm-eiving systems. either of which isadaptcd to he used in connection with cithcr ot' the forms of transmission systems shown in Figs. 1 and 2; Fig. 5 is a view ot a modified form of transmission systcni: Fig. 0 is a view of a further modified form of transmission system: Fig. 7 is a view of a receiving system adapted to be used in connection with the transmission system shown in Fig. 6: Fig. 3 is a view of a further modified form of tansmission system; Fig. 9 is a view of a receiving svstcm adapted to he used in connection with the transmission svstcm shown in Fig. 8: 'Fig. 10 is a view of a modificd form of receiving system: and Fig. ll is a view of a further modified form of recciving system.

Referring to the drawings and partic,

ularly to Fig. 1. one form of transmission system constructed in accordance with this invention comprises two open aerial. circuits 25 and 30. arranged to emit. respectively two series or trains or high frequency oscillations of different frequencies respectively, for instance, of 300,000 per second and 250,- 000 per second, respectively. These two open aerial circuits 25 and 30 include respectively an antenna 31. grounded as at 32 through an inductance 33, and an antenna 3%, grounded as at 35 through an inductance 36. The two inductanccs and 36 form the secomlarics of two transformers 40 and 41. which include respectively two primary coils or inductanccs 42 and 43. which are arranged respectively in the two closed 0scillatory circuits 44- and 45. which include respectively two sparl; gap devices 46 and 47. and two variahlc condenser-s48 and 49. These two closed oscillatory circuits 44 and 45 are adjusted in a well-known manner in relation to their respective open aerial circuits Q5 and 30 to cause the open aerial circuits and 1&0 to be effectively stimulated by them. The two variable condensers 4-9 and 49 arc arrangcd to he charged from any suitable source of direct current of high voltage. as. for instance. from a direct cur rent generator 50 giving a otential of about 500 volts. one brush 5] of this gene ator being connected through a rheoslat 5Q. choke coil 53 and conductor 5-} to one side of the variable condcnscr 48. and through a branch conductor 5:). cholcc coil 50 and conductor 57 to one side of the variable condenser 49. The other brush 51% of the generator '50 is connected through a conductor 59. choke coil (30 and conductor 01 to the other side of the variable condenser 48. and through a rhco stat (t5. cholcc coil (36 and conductor (37 to the other side of the variable condenser 49.

For simultaneously impressing upon the two series of high trcip'lcncv waves of oscillations emitted hv the open aerial circuits 25 and 30. respectively. two series of periodic amplitude variations having the same li'crpicncies respectively. for instance. of 20.000 per second. two secondary frequency imposing devices or tonc circuits comprising respectively an inductance 75 and a variable condenser 76 in series therewith, and an inductance 77 and a variable con denser 78 in series therewith are shunted rcs'pcctivclv about the two variable condonsnrs 4-8 and 19.

For producing a predetermined phase relationship between the two series of priodic amplitude variations, the two tone circuits 75, 76 and 77, 78 are operatlvely connected by an intermediate circuit 100, which includes two coils 101 and 102, and a primary variable condenser 103. Shunted around the primary condenser 103 is a secondary variable condenser 104-, which is pro vided with a key 105 whereby the condenser 104 will be thrown into operation. The two coils 101 and 102 are inductively connected respectively to the two coils 75 and 77 of the two tone circuits. This intermediate circuit 100 may be adjusted by varying the various elements of this circuit and by varying the coupling between the coils between the intermediate circuit and the tone circuits so that when the switch 105 is closed a predetermined difference in phase, for instance, of 90 will be produced between the two series of periodic amplitude variations of the emitted waves.

To adapt the transmission system shown in Fig. 1 to be used for transmitting telephonic messages, a coil 110 may be included inthe intermediate circuit 100, and an auxiliary circuit 111, including a coil 112 and a telephone transmitter or microphone 115 may be arranged so that the coil 112 of the auxiliary circuit will be acted upon inductively by and will react inductively upon the coil 110 of the intermediate circuit 100. In this arrangement, when the switch 105 is closed and the operator speaks into the telephone transmitter'115, the interaction I between the two tone circuits 75,76, and 77,

78 through the intermediate circuit 100 will he modified 'in such a manner that the phase difference between the two series of periodic amplitude variations of the system will be varied in accordance with the sound waves received by the telephone transmitter. 115.

In the operation of the transmission system shown in Fig. 1, with the switch 105 closed and the generator 50 in operation, t h\ two open aerial circuits 25 and 30 will be caused to emit two continuous series of electro-radiant waves having wave frequencies of, for instance, 300.000 and 250,000 per second respectively. The amplitude of each of these series of waves will be periodically varied in a uniform manner and at a predetermined frequency, the frequency of these periodic modifications in amplitude being the same in both series of waves emitted, and as a result of the interaction between thetwo tone circuits 75, 76 and 77, 78 and the intermediate circuit 100, the difi'erence in phase between these two periodic modifications will be. for instance, substantially 90. \Vhen the switch 105 is open, the variable condenser 101% will be cut out of operation and consequently the interaction between the two. tone circuits 75, 76 and 77, 78 through the intermediate circuit 100 will 'be varied and will decrease the phase difference between the two series of periodic amplitude variations from 90 to 0, so that the two series of amplitude variations will be in the same phase. '-These two series of emitted waves thus periodically modified in amplitude may be selec-' The two open aerial circuits 200 and 201 are arranged to be energized respectively by two high potential batteries 215 and 216, or other suitable source of high potential direct current. which are arranged to act respectively through two electrionic or thermionic valves 217 and 218, which are in series respectively with the two batteries 215 and 216, and in shunt circuits controlled respectively by switches 215' and 216' around the two coils 205 and 210 of the two open circuits 200 and 201 respectively. Each of these valves 217 and 218 comprises an evacuated glass bulb, or other suitable container, 220, in which is arranged a plate electrode 221, a grid 222, and a filament 223, which is arranged to be heated by a battery 224 acting through a rheostat 225. The two grids 222, 222 are connected to their respective open circuits by two corresponding circuits including respectively two inductances 225 and 226, and two auxiliary coils 227 and 228. The coil 227 is inductively and adj ustably coupled to the coil 205, and the coil 228 is inductively and adjustably coupled to the coil 210. shunted around the two inductances 225 and 226 respectively are two variable condensers 230 and 23].

In the arrangement thus far described,

when the switches 215' and 216,are closed,

the thermionic valves 217 and 218 will be caused to operate through the energy supplied by the batteries 215 and 216 to cause thermionic valve 240, of any well-known or suitable construction, is provided. In the form shown, this auxiliary valve 2&0 includes an evacuated glass bulb 241', or other Suitable container, in which is arranged a plate electrode 242, a grid 243, and a tila ment 244. The filament 244 is arranged to be heated by a battery 245 acting through a rheostat 246. The auxiliary valve 240 is in a circuit controlled by a switch 249 and including a high potential battery 250, or other sourceof high potential, a main inductance 251,. and an auxiliary inductance 252. A variable condenser 253 is shunted around these two inductances 251 and 252, and is thus arranged in a closed auxiliary circuit 254 containing these inductances. This closed circuit 254 is adjusted so that its own free period of oscillation will be equal to the period of amplitude variations which it is desired to impress upon the emitted high frequency wave. The auxiliary in ductance 252 of this closed circuit is arranged to act inductively upon the main inductance 226 of the thermionic valve 218, which is connected to the auxiliary open circuit 201. The grid 243 is in a circuit including a coil 254'. which is inductively coupled to the main inductance 251 to be reacted upon by the current in the auxiliary circuit 254. The thermionic valve 240 is inductively connected with the thermionic valve 217, which controls the main open circuit 200. by means of a closed oscillatory circuit 255. which contains a variable con denser 256, a main inductance 257. and a secondary inductance 258. A variable condenser 260 is arranged to be shunted around the variable condenser 256 and is controlled by a switch-201 which is arranged to con trol the variable condenser 260 and which allows operation at the will of an operator. The main inductance 257 oi the intermediate circuit 255 is inductively coupled to the. main inductance 251 of the circuit of the auxiliary valye 240. and the secondary inductance 258 of the intermediate circuit 253 is inductively coupled to the inductance of the'thermionic valve 217 of the ma n open circuit 200. The variable condenser 250 of the intermediate circuit 255 may be adjusted to .give a desired phase relation between the series of periodic amplitude variations emitted by the main open circuit 200 and the series of periodic amplitude variations emitted by the secondary circuit 201. The arrangement is such that when the switch 261 is 'closed. the variable condenser 256 may be adjusted to produce a phase (litterence, for instance. of betwen these two series of periodic amplitude variations.

. To adapt the transmission system shown in Fig. 2 to be used for transmitting telephonic messages. a coil 262 may be included in the intermediate circuit 255 and an auxiliary circuit 203 including a coil 264 and a telephone transmitter or microphone 265 may be arranged so that the coil 264 of the auxiliary circuit. 203 will be acted upon in ductively by and will react inductively upon the coil 262 of the intermediate circuit In this arrangement. when the switch 261 is closed and the operator speaks into the telephone transmitter 205. the operation of the intermediate circuit 255 will be modified in such a manner that the phase difference between the two series of periodic amplitude variations of the system will be varied in accordance with the sound waves received by the telephone trz'insmitter 205.

In the operatiim oi the transmission system shown in Fig. 2. when the switches 215. 216'. 249 and "201 are closed. the two open aerial circuits 200 and 201 will be caused to emit two continuous series of electro-radiant waves having frequencies of. tor instance. 300.000 and 250.000 per second respectively. and periodic variations in the amplitude of these two series of waves will be ctl'ectcd as a result of the operation of the auxiliary valve 240 acting through the auxiliary circuit 254 and through the intermediate circuit the frequency of these amplitude variations bein c the same in both series of waves. for instance. 20.000 variations per second. These two series of amplitude variations will have a difference in phase of. for instance. 00. depending upon the adjustment of the variable condenser 250' 'hen the switch 201 is open. this phase d fference will be modified to such an extent as to render the system ineffective. as will appear hereinafter.

In Fig. 3 is shown one form ot receiving system constructed in accordance with this invention which may be. utilized to rc eive waves transmitted trom either of the transm ssion systems shown in Figs. land 2. or from any other similar or suitable tran mission system. This form oi' receiving; system comprises a divided open aerial rcceivimr circuit 275. including an antenna 270. which is grounded as at 277 through two branch cir cuits. including respectively two variable condensers 27 and 270 and two coils 280 and 281. The circuit comprising the antenna 270 and the branch circuit containing the condenser 27% and coil 280 is tuned to one of the high frequencies of the transmission system. tor inst ancc. to 300,000 oscillations per second. while the circuit comprising the antenna 270 and the other condenser 27!) and the corresponding coil 281 is tuned to the v other high frequency of the transn'iission system, for instance. to 250.000 oscillations per second. The. two coils 280 and 281 form the primaries of two transformers 28 and 284. having? secondary coils 285 and 286. which are inclosed oscillatory circuits 287 and 288, which are tuned respectively to the I a two high frequencies of the open reeelvlng circuits, for instance, 300,000 per second and 250,000. per second, and which are arranged to controltwo detectors 290 and 291 of any well-known and suitable construction, for instance, as in the form shown, two gaseous detectors of well-known construction. These two detectors 290 and 291 are arranged to control two circuits 292 and 293, which include respectively two sources of high potential direct current, as, for instance, two high potential batteries 294 and 295, and two primary coils 296 and 297, which are arranged so that their longitudinal'axes lie in thesame plane and intersect at right angles. Each of these two primary coils 296 and 297 is arranged intwo aligned spaced sections and these two primary coils 296 and 297 are arranged respectively in two closed oscillatory circuits 300 and 301 including respectively two variable condensers 302 and 303, which are shunted around theprimary coils 296 and 297 respectively. These two closed circuits 300 and 301 are each tuned to the frequency of the amplitude variations of the transmission system, for instance, to 20,000 oscillations per second. Surrounded by the coil sections of the two primary coils 296 and 297 and in a plane therewith are eight secondary coils 310, which are arranged in series to radiate substantially from the point of intersection of the axes of the two primary coils 296 and 297. These secondary coils 310 are spaced equi-angularly around their center of radiation so that the longitudinal axes of the two primary coils 296 and 297 will respectively bisect the angles formed between corresponding consecutive secondary coils, as shown in the drawings. The two pairs of primary coils 296 and 297 correspond to the stator of a two phase induction motor, whose wound rotor is made up of windings 310. If only one phase is excited, as would be the case if detector 290 was responding to an interfering signal, an alternating magnetic field is set up between the two halves of coil 296. This field cuts four of the coils of the rotor 310, which are connected at their inner ends, so that the resulting induced, E. M. F.s cancel in each adjacent pair of rotor coils, thus leaving detector 315 unaffected. The same is true for an incoming interfering signal received by detector 291 and a similar result would be produced if both detectors 290 and 291 were simultaneously subjected to an interfering signal. However, if a signal is received from one of the above described transmitters, which are capable of emitting waves whose phase difference is 90, the two magnetic fields set up between the halves of coils 296 and 297 will differ in phase by 90,

the result being, the well known rotating ma etic field of, say, the induction motor. l li e action of th rotati g field'upon the add. It is to be remembered, that, as mentioned above, in rotor'coils connected together at their inner ends, the induced E. M. F.s oppose. Thus a voltage will be generated in rotor 310 by the alternating field, when displaced from the positionshown in the drawing (Fig. 3). Instead of actually moving the field coils 296 and 297, their resultant magnetic field rovolves, inducing thereby a voltage in coils 310 of the same frequency, as that supplied to the field coils 296 and 297. The secondary coils 310 are in a closed oscillatory circuit 311, which includes a variable condenser 312 and which is tuned to the secondary frequency of the system multiplied by the number of coils, for instance, to 160,000 oscillations per second. This closed circuit 311 is arranged to control a gaseous detector 315, or any other suitable detector, through an interrupter 319. A shunt circuit 320, controlled by a switch 321, is provided around the interrupter 319 to render the interrupter either effective or non-efiective at the will of the operator. The gaseous detector 315 is arranged to control a circuit 323 including a high potential battery 324, or other source of current, a telephone 325, or a relay, or any other wellknown or suitable receiving instrument.

In the operation of the receiving system shown in Fig. 3, when two series of waves from the transmission system having wave frequencies of respectively 300,000 per second and 250,000 per second and periodic amplitude variations of 20,000 per second in each series are received by the open aerial circuit 275, the two detectors 290 and 291 are caused to operate so as to emit unidirectional current impulses thro, h the two control circuits 292 and 293. These impulses will have a high frequency of 300,000 and 250,000 per second respectively in the two control circuits 292 and 293 and a secondary frequency of 20,000 persecond in both these circuits. It, now, there should be a phase difference of substantially 90 in the periodic modifications of the two series of received waves, two series of electrical oscillations having substantially the same frequency and intensity but having a difference in phase of substantially 90 will be set up in the two coils 296 and 297. The result of the magnetic field of these two coils will be constant in strength and will rotate uniformly, making one complete revolution for each cycle of the secondary frequen y of 20,000 per second. This rotating magnetic field will induce in the closed oscillatory circuit 311 containing the secondary coils 310 electrical oscillations having a frequency q al to t e secondary "frequency of the system. This oscillation of the closed circuit 311 will cause the operation of the detector 315 which will cause unidirectional impulses having a frequency of 120.000 per second.

lVhen the receiving system shown in Fig. 3 is used to receive telegraphic signals. the switch 321 is left open to render the interrupter 319 eilective and the interrupter is rotated at a constant rate to interrupt the circuit at, for instance. 1,000 interruptions per second, so that when the current inipulses are set up in the controlled circuit 323. these impulses ivill be interrupted at the rate of 1.000 interruptions per second and the telephone will be caused to emit a tone having 1,000 vibrations per second,and which will be audible.

lYhen the s; stem shown in Fig. 3 is used to receive telephonic messages, the switch 321 is closed to render the interrupter 319 ineffective. and the controlled circuit 323 will then remain unbroken, and the telephone receiver 325 will be caused to emit sound waves as a resultof and corresponding to the ariations of the phase difference between the two series of amplitude variations of the waves received by the system.

\Yhen a relay or other similar instrument is substituted in Fig. 3 for the telephone receiver the switch 321 is lrept closed, and when a wireless signal is being received unidirectional impulses will be set up in the cir uit as hercinbetore described, and as a result of these impulses the relay, or other similar instrument. witl be operated.

in the case of static shocks or impulses acting upon the open at ial circuit 275 of the receivingsystem shown in Fig. 3. both of the controlled circuits 292 and 293, if affected. would be aflected simultaneously, and hence would cause the circuits to oscillate. if at all. in the same phase. It currents of the same phase and intensity should pass through the coils 200 and 297. the resultant. magnetic field would not rotate but would remain fixed midway between the axes of the two coils. and oscillations will not be set up in the closed circuit 311, and consequently the detector 15 and the Controlled receiving instrument 325 will be practically unafi'cctcd.

in Fig. l is shown a modified form of reccivin; system arranged to operate with either of the transmission systems shown in Figs. 1 and 2. or with any othe suitable tran mis ion ystem. This modified iorni compris s a divided open aerial circuit 350 constructed as hereinbcl ore described and comprising an antenna 351 which is grounded as at 152 through two branch circuits ineluding respectively two variable condensers 353 and 35 1, and two coils 355 and 356. The circuit through the antenna 351, condenser 3153 and coil 355 is tuned to one of the high frequencies of the received waves, and the circuit through the antenna 351, condenser 354 and coil 350 is tuned to the other high irequencyol the received waves. The coils $55 and 350 are inductively coupled respectively to two se midary coils 357 and 357, which are arranged respectively in two closed oscillatory circuits 358 and 359, which are tuned respectively to the corresponding circuits of the primary coils 355 and 356. These two closed circuits 358 and 359 are arranged to, control two detectors 360 and 361 of any well-known or suitable construction. for instance, two gaseous detectors of well-knmvn construction, which are arranged to control two circuits 3G2 and 362 containing re pectively two coils 364 and 364 and two high potentialbatteries 365 and 365. or other suitable sources of high potential. The two coils 36a and 364 are arranged in two closed oscillatory circuits 366 and 367, which include respectively two variable condensers 368 and 368. These two closed circuits 366 and 367 are tuned to the secondary frequency of the received waves, for instance. to 20,000 oscillations per second, and are inductively coupled to two closed oscillatory circuits 309 and 369,which are tuned to the secondary frequency of the received waves, for instance. to 20,000 oscillations per second, and which are arranged to control two secondary detectors 370 and 371. The two secondary detectors 370 and 371 may be of any well-known or suitable construction. and in the form shown are gaseous 'detectm's oi well-known construction. These secondary detectors are ar- "anged to control two circuits 372 and 372, which include respectively two primary coils 373 and 374. and two high potential bat-- teries 375 and 375. The primary coils 373 and 374 are respectively in two closed o cillatory circuits 376 and 377. which include res 'iectively two variable condensers 378 and 378. The two coils 373 and 374 are arranged so that their longitudinal axes lie in the same plane and intersect at right angles. and cach o'l" these coils is in the form of two aligned spaced sections. Surrounded by the coil sections of the two primary coils 373 and 37 1 and in a plane therewith are eight secondarv coils 380 which are arranged to tllfil l'tullilll substantially from the point of intersection of the axes of the two prima y coils 37 and 374. 'lhese secondary coils 3180 are spaced equi-angularly around their enter ol radiation. so that the longitudinal axes of the two primary coils 373 and 374 will respectively bisect the angles formed between corresponding consecutive secondary coils. as shown in the drawings. The

369 respectively.

secondary coils 380 are in a closed oscillatory circuit 381, which includes a variable condenser 382, and which is arranged to control through an interrupter 383 a detector 384 of any suitable construction, for in stance, a gaseous detectorof well-known construction. A shunt circuit 385, controlled by a switch 386, is shunted around the interrupter 383 to render the interrupter either effective or non-effective at the will of the operator. The detector 384 is arranged to control a circuit 387' containing a high potential battery 388, or other source of high potential current, and a telephone 389, or other suitable receiving instrument or device.

When the system shown in Fig. 4 is used for receiving telegraphic messages, the switch 386 is kept losed and the interrupter 383 is arranged to be rotated at a uniform rate by a motor or any other suitable means (not shown) to interrupt the circuit periodically at a frequency, for instance, of 1,000 interruptions per second, so that when a signal is beingreceived by the open circuit 350, an audible sound will be .produced in the telephone 389.

For producing electrical beats in the two closed oscillatory circuits 369 and 369 controlling the secondary detectors 370 and 371, an electrical oscillator, including a thermionic valve 390 of any well-known or suitable construction, is provided. This valve is arranged to control a circuit including a battery 391 and a coil 392, which is in a closed oscillatory circuit 393, including a variable condenser 394. This closed circuit 393 is adjusted so that a predetermined number of oscillations per second will. be set up in this closed circuit 393 as a result of the action of the valve 390. In the present case, this closed circuit is adjusted or tuned to produce, under the action of the valve 390, continuous oscillations of a frequency either of 1,000 per second above, or 1,000 per second below the secondary frequency of the system; in-0ther words, to produce either 19,000 or 21,000 oscillations per second. The coil 392 is connected through a variable contact 395 and two variable condensers 396 and 396 with the two closed circuits 369 and By this arrangement, oscillations having a frequency either of 19,000 or 21,000 per second will be superimposed in the closed circuits 369 and 369 on the oscillations of 20,000zper second which are produced in these circuits by. the action of the received waves, and consequently.

electrical beats having a frequency of 1,000 per second will be produced in each of these two closed circuits 369 and 369. If the secondary oscillations of 20,000 per second in these two closed circuits 369 and 369 have a phase difference of 90, the electrical beats set up as just described in these circuits will also have a phase difference of 90.

In the operation of the receiving system shown in Fig. 4, the oscillatory circuits 376 and 377 controlled by the secondary detectors 370 and 371 are tuned to the beat frequency of the two closed circuits 369 and 369 of, for instance, 1,000 oscillations per second, and the closed circuit 381, controlling the final detector 389, is tuned to the beat frequency, for instance, to 1,000 oscillations per second. The remaining circuits are tuned as hereinbetore described. Now when two series of waves having high frequencies respectively of 300,000 and 250,000 oscillations per second and having imposed thereon periodic amplitude variations of 20,000 per second are received by the aerial circuit 350, corresponding oscillations are set up in the closed circuits 358 and'35-9, which act through the primarydetectors 360 and 361 to set up oscillations having a secondary frequency of 20,000 per second in the closed circuits 366 and 367. These secondary oscillations produce corresponding oscillations in the closed circuits 369 and 369 which control the two secondary detectors 370 and 371. Electrical beats of 1,000 per second are then caused to be set up in the closed circuits 369 under the action of the thermionic valve 390. These .beats act through the secondary detectors.. ;370 and 371 to produce electrical oscillations of substantially the same frequency of 1,000 per second and of substantially the same intensity in the two closed circuits 376 and 377, but having a phase difference of The effect of these oscillations flowing through the two primary coils 373 and 374 will be to set up a mag netic field which will remain substantially constant in strength but which will rotate uniformly, making one complete revolution for each beat cycle of the beat frequency.

Electrical oscillations having the beat frequency will thus be set up in the closed circuit 381 containing the eight secondary coils 380, and these oscillations will act through the interrupter 383 and through the final detector 384 to produce unidirectional impulses through the controlled circuit 387, 388 through theitelepho-ne or other receiving instrument 389.. Through the action of the interrupter 383. these impulses will be interrupted ifdesired to cause the telephone 389 to reduce an audibile sound or tone.

' f, now, the'operation of the transmission system should be modified so as to reduce the phase difference between the two series 374 in the receiving system would cease to rotate, and consequently little, if any, current would be set up in the closed circuit 381, and the receiving instrument 389 would cease to operate.

When the receiving system shown in Fig. 4 is used for receiving telephonic messages from a corresponding transmission system, such, for instance, as either of the transmis sion systems shown in Figs. 1 and 2, the switch 386 should be left closed to shortcircuit the interrupter 383 of the receiving system. and the slight variations in the difference in phase of the two series of periodic amplitude variations of the received waves due to the action of the telephone transmitter 115 in Fig. 1, or 265 in Fig. 2, would slightly vary the action of the primary coils 373 and 374 accordingly and cause corresponding variations in the oscillations in the closed circuit 381 and consequently corre sponding variations in the current in the controlled circuit 387. These variations in the current in the controlled circuit 387 would cause the telephone receiver 389 to emit sound waves corresponding to the sound waves acting upon the telephone transmitter 115 in Fig. 1, or 265 in Fig. 2, of the trans mission system. When used for telephony, the beat frequency at the receiver is adjusted to a frequency substantially above audibility, for instance, to 10,000 cycles per second. instead of 1,000 cycles per second.

In Fig. 5 is shown a further modified form of transmission system constructed in accordance with this invention. This modi' fied form comprises two open aerial circuits 400 and 401, which include respectively an antenna 402 grounded as at 403 through a coil 404 and an alternator 405, and an antenna 406 grounded as at 407 through a coil 40S and an alternator409. These two open circuits 400 and 401 are tuned respectively to two different frequencies, for instance, to 200,000 and 100,000 oscillations per second, and the two alternators 405 and 409 are arranged to generate alternating current. of the same frequencies respectively as the frequencies to which the open aerial circuits 400 and 401 are tuned.

For impressing periodic amplitude varia- Lions of the same frequency and either of the same phase or diherent in phase upon the high frequency oscillations set up in the two open circuits 400 and 401 by the alter nators 405 and 400. the two coils 404 and 408 are arranged to surround respectively two corresponding sides of two soft iron rectangular cores 415 and 410, which are air ranged to he magnetized respectively by two magnetizing circuits 411' and 418, which include respectively two coils 410 and 420, two batteries 421 and 422. and two rheostats or variable resistances 423 and 424. the coils 410 and 420 being arranged to surround two corresponding sides of the two cores 415 and 416. A. third side of each of the cores 415 and 416 is surrounded by a. coil 425, and these two coils 425 are respectively in two intermediate circuits 426 and 427 including respectively a variable inductance 428 and a secondary coil 429, and a variable condenser 430 and a secondary coil 431. Arranged between the secondary coils 429 and 431 is an auxiliary circuit 435 including two primary coils 436 and 437, and an alternator 440, which is arranged to set up alternating current having the same frequency as the frequency of the periodic amplitude variations which it is desired to impress upon the oscillations in the open aerial circuits 400 and 401, for instance, having a frequency of 20,000 alternations per second. The primary coils 436 and 437 are inductively coupled to the secondary coils 429 and 431 in such a manner that when oscillations are set up in the closed auxiliary circuit 435 by the alternator 440 corresponding oscillations will be inductively set up in the two intermediate circuits 426 and 427 and will act upon the two cores 415 and 416 to periodically vary the free magnetization of the two coils 415 and 416 and consequently to periodically vary the inductant effects of the two coils 404 and 408 and throw the open aerial circuits 400 and 401 into and out of tune at the frequency of the alternator 440 of the auxiliary circuit 435. thus periodically varying the amplitude. of the electroradiant oscillations emitted by the open circuits 400 and 401 at the same rate. for instance, of 20,000 per second.

For varying the phase relationship in the periodic amplitude variations of the two series of oscillations emitted by the open aerial circuits 400 and 401. a variable condenser 441 is in a circuit 442, shunted around the variable condenser 430 and controlled by a key or switch 443. These variable condensers 430 and, 441 are preferably so adjusted that when the key 443 is closed and the system is in operation, a phase difference of approximately 90 will be produced between the two series of periodic amplitude variations of the emitted waves. and when the key 443 is open, this phase difference will be reduced to 0. so that the two series of periodic amplitude variations willbe in the same phase.

For adapting the system shown in Fig. 5 for use in transmitting telephone messages. a tclcphone transmitter o1 microphone 4-15 is arranged in a circuit 446 shunted around the key 443 and controlled by a swit h 447. When it is desired to use the system for transmitting telegraphic 1nessagc=- the switch 447 is left open and the key 443 is used for transmitting the messages. but when it is desired to use the system for transmitting telephone messages, the key 443 is left open and the switch 447 is kept closed.

The transmission system shown in Fig. 5 may be utilized in connection with a receiving system such as is shown in Fig. 4, or any other suitable receiving system, to transmit either telegraphic or telephonic messages, and when so used will cause the operation of a receiving device as a result of a difference in phase between the two series of periodic amplitude variations, as hereinbefore described.

In Fig. 6 is shown a modified form of transmission system constructed in accordance with this invention and arranged to emit three series of high frequency oscillations having three different frequencies respectively, and provided with means for impressing upon the threeseries of oscillations three series of periodic amplitude varlations having the same frequency, and means for varying the phase relation between the three series of periodic amplitude variations.

This modified system shown in Fig. 6 comprises three open aerial circuits 460, 461 and 462, each of which comprises an antenna 465 grounded as at 466 through a coil 467 and a high frequency alternator 468. These three open circuits 460, 461 and 462 are tuned respectively to three different frequencies, for instance, to 200,000, 150,000 and 100,000 oscillations per second. The three alternators 468 are arranged to generate electrical alternations having the same frequencies respectively as the frequencies to which the open aerial circuits 460, 461 and 462 are tuned.

For impressing three series of periodic amplitude variations upon the three series of oscillations set up in the three open circuits 460-, 461 and 462, the three coils 467 surround respectively three corresponding ides of three. magnetic soft iron cores 470, which are arranged to be magnetized by three batteries 471 acting through three rheostats 472 and three coils 473 which surround respectively three corresponding sides of the three cores 470. For periodically varying the magnetization of the cores 470, a three-phase high frequency alternator 475 is arranged to deliver energy to athreephase transformer 476 which includes three primary coils 477. These primary coils 477 are inductively coupled respectively to three secondary coils 47 8, which are respectively 1 in three intermediate circuits 479,,including respectively three coils 480 which surround corresponding sides of the cores 470 respectively. Two of these intermediate circuits 479 include respectively a variable inductance 481' and a variable condenser 482. The variable inductance'481 and thevariable condenser 482 may be so adjusted that the three series ofperiodic amplitude variations set up in the three open circuits 460,

461 and 462 by the action of the three-phase alternator 475 will occur with a phase difference of, for instance 120 between each series of periodic amplitude variations and the succeeding series.

For controlling the open aerial circuits ranged to engage the surface-of the commu tator along a line which is parallel with the axis of rotation of the commutator, and are arranged in pairs 486, 487 and 488, 489 to engage the two spaced portions of the commutator respectively. Cylindrical surfaces of the two spaced portions of the commutator are made up respectively of two aligned series of equal conducting-segments separated by two aligned series vof equal insulating segments. These segments are so arranged that aS the commutator rotates each aligned pair of conducting segments are moved simultaneously into and simultaneously out of engagement with the pairs of brushes 486, 487 and 488, 489 respectively. One pair 486 and 487 of the brushes are connected respectively by conductors 491 and 492 to one side of the variable inductance 481 and to a key or switch 493, which i arranged to swing about a fixed axis and to be moved into and out of engagement with three aligned spaced contacts 494, 495 and 496 fixed in the path of the key. The key 493 comprises two conducting portions which are separated by an insulating portion 497, and the arrangement of the insulated portion is such that when the ke 493 is closed upon the contacts 494, 495 an 496, the key will electrically connect the contact 4 94 with the conductor 492, and the contact,

495 with the contact 496, but will not clear trically connect the contact 494 with the contact 495. The other pair of brushes 488 and 489 are connected respectively by two conductors 498 and 499 to the fixed contact 496 and to one side of the variable conf denser 482. The other sides of the variable inductance 481 and the variable condenser 482 are connected respectively by conductors 500 and 501 to the two fixed contacts 494 and 495.

' In the operation of the transmission sys I tem shown in Fig. 6 for transmitting telegraphic messages, the commutator 485 'is caused to rotate at such a rate as to cause the circuits controlled by the brushes 486 to 489 to be interrupted at a rate of, for instance, 1,000 interruptions per second, and

Ill

the key 493 is used to send the telegraphic signal. As long as the key 493 is open, the variable inductance 481 and the variable condenser 482 will be included in their corresponding intermediate circuits 470 and will act upon these circuits to cause the three series of periodic amplitude variations to be impressed upon the open aerial circuits 460, 461 and 4t; multaneously and in the same phase, but when the key 4:93 is closed, the variable inductance 481 and the variable condenser 482 will be simultaneouSly and periodically short-circuitcd automatically at a. rate controlled by the commutator 4H5, for instance, a-' a rate 'of 1.000 per second, and each time that these elements are short-circuitcd the phase relation between the three series of periodic amplitude variations will be modified in such a 'manner as to produce a ditt'erence in phase switches 403 and 514 are both kept closed.

'lhe telephone message may then be transmitted by speaking into the telephone transmitter 511.

In F i g. T is shown a receiving system constructed in accordance with this invention and arranged to receive either telegraphic or telephonic messages transmitted by the transmission system shown in Fig. 6, or by any other suitable transmission system. This receiving system includes three open aerial circuits 525 which are tuned respectively to the three ditlerent frequencies of the waves intended to be received. for instance, to 200.000, 150.000 and 100.000 oscillations per second. These three open circuits 525 are inductively coupled to three closed oscillatory circuits 5%. which are correspondingly tuned to the same frequencies respectively as the open circuits. These closed circuits .320 are arranged in a wellknown manner to control respectively three primary detectors 5:27 of any well-known or suitable fornn the detectors shown being gaseous detectorsof well-known form. These primary detectors 527 are arranged to control respectively three circuits 528 including respectively three primary coils 529 apd three high potential batteries 530, or other suitable sources of: electric energy. The three primary coils 520 are arranged reclosed circuits 536, .337 and 538 are each tuned to the secondary frequency of the systenn for instance, to 20.000 oscillations per second. The primary coils 540. 541 and 542 are each divided into two spaced aligned sections and are so arranged that their longitudinal axes lie in the same plane and interf sect at a common point about which these axes are equi-angularly spaced. Surrounded by the sections of the three primary coils 540. 5M and 542 are six secondary coils 545, which are arranged so that their longitudinal axes are in a plane with the longitudinal axes of the primary coils and radiate equia-ngularly from the point of intersection of the longitudinal axes of the primary coils. The secondary coils 545 are also arranged so that the longitudinal axes of each pair of opposed coils coincides with a line which bisects the angle formed bet een the longitudinal axes of two corres ronding primary coils. The sccondanv coils 545 are .in a closed oscillatory circuit 546. which includes. a variable condenser .74? and which is tunedto six times the secondary frequency of the system. which in the prcsmt nstance will be to 20.000 oscillations; per second. This, closed circuit M6 is arranged to control a secondary gaseous detector 5 th of well. known constriction. This secondary detector A? is arranged to control a circuit- 549 inciuding a high potential battery 5.30

and a primary coil 552. The primary coil is in a closed circuit- 553 which includes a variable condenser 715i and vhich is, tuned to the third frequencyofthcsyst'eni. the third frequenev being determined by the coinmutator -l-H5 of the transmission system shown in Fig. 6, and being. for instance. 1000,05- cillations per second. The primary coil.

is inductively connected toa secondary coil which is in a closed circuit 55 including a variable condenser 55?. and

which is tuned to the same frequency asthe;

closed circuit .353. The clo:=cd circuit 556 is arranged to control an auxiliary detector 558. which in turn is arranged to ontrol a circuit 535 including a high potential bat tcry 500 and a telephone 501. or other suitable receiving device. v

in the operation of the receiving system shown in l ig. T. when three series of waves from the, three transmitting systems shown in Fig. 6 are received by the three open cirup respectively in the three closed circuitscuits 525, three series of oscillations of a frequency of 20.000 per second will be set netic field around these coils which Will,

alternately rotate at a rate-o1 20,000revolutions per secr'mdQand remain stationary at the rate of 1,000 times per second, and the effect of this magnetic field upon the secondary coils 54.5 will be to set up an oscillating current of 20,000 oscillations per second in the closed oscillalory circuit 546 containing these secondary coils, and the amplitude of these oscillations will be varied periodically at, the rate of 1,000 variations per second owing to the interruptions of' 1,000 per second in the rotary movementof the magnetic field. These oscillations will act through the secondary detector 548 to set up current impulses of 120,000 per second, periodically varied in amplitude at the rate of 1,000 variations per second, in the circuit 549 controlled by the secondary detector.

These impulses thus modified will set up oscillations of 1,000 per second in the closed circuit 553 which will act to set up corresponding oscillations in the closed circuit 556, which in turn will act through the auxiliary detector 558 to cause unidirectional impulses having a frequency 0 1,000 per second to flow through the circuit 559 controlled by the auxiliary detector 558, and consequently an audible tone will be produced in the telephone receiver 561.

In Fig. 8 is shown an improved transmission system constructed in accordance with this invention, comprising four open aerial circuits 570, 571, 572 and 573, each of which includes an antenna 576 grounded as at 577 through a coil 578 and a high fre uency alternator 579. These four open circuits 570 to 573 are tuned respectively to four difierent frequencies, for instance, to 200,000,

160,000, 120,000 and 100,000 oscillations per second, and the corresponding four alternators 579 are arranged to generate alternations of the same frequencies respectively as the frequencies to which the open circuits 570 to 573 are tuned. i

For impressing periodic amplitude variations upon the four open circuits 570 to 573,

four rectangular soft iron cores 580 are arrangedto extend through the four coils 578 respectively. These cores are arranged to be.magnet1zed to a suitable degree respectively by four batteries 581 acting res ectively through four rheostats 582 and our magnetizing coils 583, which are wound ranged to generate alternations of 20,000 per second and 21,000 per second respectively in two closed circuits 587 and 588, each of which contains two primary coils 589 and '590, and 591 and 592.. The primary coils 589 and 590 are inductively connected to the secondary coils ,593 and 594, which are respectively in two. closed intermediate circuits 595 and 596, which contain respectively two coils 597 and 598, which surround corresponding portions of the two cores 580 of the two open circuits 570 and 571.' These two closed intermediate circuits 595 and596 also contain respectively a variable inductance 599 and a variable condenser 600. The two primary coils 591 and 592 are inductively connected to two secondary coils 605 a and 606, which are in two intermediate closed circuits 607 and 608, which include respectively two coils 609 and 610 which surround respectively corresponding portions of the two cores 580 of the two open circuits 572 and 573. These two intermediate circuits 607 and 608 also contain respectively a variable condenser 611 and a variable inductance 612. For short-circuiting the two variable condensers 600 and 611, a switch 613 is arranged to swing into and out of engagement with four fixed contacts 614, two of which are connected respectively by two cohductors 615 to the opposite sidesof one of the variable condensers 600, and the other two of which are connected respectively by a conductor 616 to the opposite sides of the other variable condenser 611. When the key 613 is closed, the two variable condensers 600 and 611 will be short-circu'ited. When the key 613 is open, the two condensers 600 and 611 will shift the phase of the two intermediate'circuits 596 and 607.

In the operation of the transmission system shown in Fig. 8, the two variable condensers 600 and 611 are so adjusted that when the alternators 579,585 and 586 arein operation and the key 613 is open, four series of continuous oscillations having WEUQ frequencies of 200,000, 160,000, 120,000 and 100,000 respectively will be emitted by the four open circuits 5'70 to 573, and upon the two series of oscillations emitted by the two open circuits 570 and 571'will be impressed respectively two series of periodic amplitude variations having the same frequency of 20,000 per second and difi'ering in phase by 91%. while upon the two series of waves emitted by the two other open circuits 572 and 573 will be impressed respectively two series of periodic amplitude variations having the same frequency of 21.000 oer second but dili'ering in phase by 90. how it the key 013 should be closed, the two variable condensers (300 and 011 will'be short-circuited and the four open circuits 570 to 573 will continue to emit four series of waves periodically varied -in amplitude, as just described, but with substantially no ditlerence in phase between the two series of periodic amplitude variations impressed upon the waves emitted by the four open circuits 570 to 573, or by the two open circuits 572 and 573.

To adapt the transmission system shown in Fig. to be used for sending either telegraphic or telephonic messages, a double telephone transmitter 617 is provided, which is of well-known construction, including a mouthpiece 618 and two microphones 619 controlled by the mouthpiece 618. These two microphones 619 are connected through two pairs of conductors 620 and 621 the two pairs of conductors 615 and 616 respectively, and the telephone transmitter 017 is provided with a switch 622 whereby the transmitter may be thrown into or out of operation. When it is desired to use the system for transmittlng telephone messages, the speed of one of the alternators 586 is increased to, for instance, 30,000 alternations per second so as to produce a difl'erence of 10,000 or more alternations per second between the two secondary frequencies of the system. The key 613 is now opened and the switch 622 is closed to throw the telephone transmitter 617 into operation. The variable condensers 000 and 601 are then adjusted so that when no sound waves are being directed into the mouthpiece 618, there will be a phase ditt'erence of substantially 90 between the two series of amplitude variations im 'iressed upon each pair of'series of emitted oscillations. Nowwhen the operator speaks into the mouthpiece 618, the resistances of the two short circuits around the two variable condensers 600 and 601 will be simultaneously varied in accordance with the sound waves received by the mouthpiece 618, and in consequence the phase difi'erence of 90 between each pair' of series of amplitude variations will be accordingly modilied and will affect the receiving System accordingly, as will appear hereinafter.

In Fig. 9 is shown a receiving systen'i con structed in accordance with this invention and. arranged to receive tour series of waves transmitted-by a suitable transmission system, as for instance, the trans-mission systern shown in Fig. 8, and hereinbefore described. This receiving system shown in Fig. 9 comprises; four open aerial circuits 625, 620, 627 and 628, which are tuned respectively to the four dillerent high frequencies of the received waves, for instance, to 200,000, 160,000, 120,000 and 100,000 oscillations per second. The four open aerial circuits to 628 are inductively connected respectively to four closed oscillatory circuits 030, which are tuned respectively to the same frequencies as the freruencies of the open circuits (525 to (52$, hese four closed circuits 630 are arranged to control four primary detectors 031, of any suitable construction, but which in the form shown are gaseous detectors of well-known construction. These four detectors 631 control respectively four closed circuits 032, 033, 034 and (535, which include respectively four high potential batteries and four primary coils 637, 638, (339 and 640. These primary coils 037 to (3-10 are arranged so that their longitudinal axes are equi-an n1larlyv arranged around a point, and so that the longitudinal axes of the two coils 637 and 338, controlled b the pair of open circuits (325 and (326, will intersect at right angles, and so that the. other pair of primary coils 030 and 0-10, controlled by the other pair of open circuits 627 and 028, will also intersect at right angles. Each 01' these primary coil is formed in two spaced aligned sections, thus allowing the insertion of a group of secondary coils 050 into the lields of these primary coils. These primary coils (Sill'to (310 are arranged respectively in tour oscillatory circuits (31-1, 642, (343 and 044, which include respectively tour variable condensers (345, 010, ($17 and 018. The two closed circuits 01-1 and 012, containing respectively the two primary coils 013T and 038, are each tuned to the same one of the two secondary l'rcquencicsol the received waves, for instance, to 20.000 oscillations per second while the closed circuits (ll-l and (3-H, containing the primary coils 039 and 0&0, are each tuncd to the other secondary frequency of the received waves, for instance, to 21,000 oscillations per second. Surrounded by the eight sections of the four primary coils 637 to 010 are a number. say eight. of secondary coils 050, which are arranged so that their longitudinal axes lie in a plane with the longitudinal axes of the primary coils 037 to 010, and radiate from and are equi-angularly disposed around the point 01 intersection of the longitudinal axes ol the primary coils. 'lhcse secondary coils 0.30 are arranged in series in aclosed oscillatory circuit 051, which includes a variable condenser 052. This closed circuit 051 is tuned to the dill'crencc of the two secondary frequencies of the system. 'lherel'ore. in the present case this closed circuit 051 would be tuned to 21.000 minus 20,000, or in other words, would be 

